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PubMed1986

Release of beta-D-galactoside-binding lectins into the cavities of aggregates of chick extraembryonic endoderm cells.

Dissociated cells from the extraembryonic endoderm of gastrulating chick embryos form aggregates when cultured in rotating flasks. The large cellular aggregates are initially solid but subsequently cavitate to form hollow, thin-walled vesicles. These cells also contain an endogenous beta-D-galactoside-binding lectin. Previous work has shown that high extracellular concentrations of this lectin are associated with decreased cell-cell adhesion [Milos, N. and S.E. Zalik: Differentiation 21, 175-182 (1982)]. We have removed the fluid contents from aggregates cultured for 24 and 48 h and tested them for the presence of lectin activity. The results demonstrate that lectin activity is detectable in a higher number of aggregates cultured for 24 as opposed to 48 h (75% vs. 28%, respectively). The lectin activity per aggregate is also higher in aggregates cultured for 24 h (180 vs. 67 hemagglutinating units, respectively, for 24- and 48-h aggregates). Thus, at the time when cells are moving apart from one another during aggregate cavitation, detectable lectin activity is released into the vesicular contents of the aggregate.

Agglutination Tests↗
PubMed1983

A marker of human foetal endoderm defined by a monoclonal antibody involves Type 1 blood group chains.

This report demonstrates that a marker of human embryonic endoderm and embryonal carcinoma cells recognized by a hybridoma antibody FC 10.2, involves Type 1 blood group chains with the sequence Gal beta 1 leads to 3G1cNAc beta 1 leads to 3Gal beta 1 leads to 4G1c. This conclusion has been reached from antigenic analyses of meconium, ovarian cyst glycoproteins, oligosaccharides and glycolipids having Type 1 or Type 2 blood group chains. From knowledge of saccharide sequences and blood group related antigens in gastrointestinal tissues of man, we deduce that the 'disappearance' of FC 10.2 antigen from the normal, differentiated cells of the adult may result from masking by additional glycosylations or other substitutions.

Acetylglucosamine↗
PubMed1990

Residual proliferative capacity in F9 teratocarcinoma stem cell cultures treated with alpha-difluoromethylornithine, an inducer of parietal endoderm differentiation.

We have previously shown that inhibition of polyamine biosynthesis by treatment with 5 mM alpha-difluoromethylornithine (DFMO) causes growth arrest and induces differentiation of F9 teratocarcinoma stem cells. The resulting phenotype is similar to that of parietal endoderm, and these differentiated cells possess no apparent proliferative capacity. In the present study, however, it is demonstrated that some of the DFMO-treated cells are not terminally differentiated. Upon a change to DFMO-free growth medium these cells eventually start to proliferate. Using a colony forming efficiency assay, it is estimated that less than 1 out of 200,000 cells retains its proliferative capacity after 6-10 days of DFMO treatment. These cells exhibit no apparent resistance to DFMO, and their population doubling time is similar to that of untreated control F9 cells. Consequently, the possible existence of a small, quiescent, cell population possessing proliferative potential must be taken into account when designing therapeutic protocols for DFMO.

Cell Differentiation↗
PubMed2006

Efficient cardiomyocyte differentiation of embryonic stem cells by bone morphogenetic protein-2 combined with visceral endoderm-like cells.

As the signals required for cardiomyocyte differentiation and functional regulation are complex and only partly understood, the mechanisms prompting the differentiation and specification of pluripotential embryonic stem (ES) cells into cardiomyocytes remain unclear. We hypothesized that a combined technology system, cocultured with a visceral endoderm (VE) - like cell line, END-2, and added cytokine BMP-2, would induce high percentage conversion of murine ES-D3 cell line into cardiomyocytes, and derived cardiomyocytes in this system would exhibit more mature characteristics. It was observed that 92% (P<0.01) ES cell-derived aggregates in this system exhibited rhythmic contractions, and the contractile areas were greater. By contrast, in ES cells cultured alone, on the feeder layer of END-2 cells, or with added BMP-2, the total percentage of beating aggregates was 19, 69 (P<0.01) and 44% (P<0.01), respectively. All the rhythmically contractile cells derived from ES cells expressed cardiac-specific proteins for troponin T. Among them, the combined system resulted in significantly increased cardiac-specific genes (NKx2.5, alpha-MHC). Transmission electron microscopy (TEM) revealed varying degrees of myofibrillar organization, and the combined system resulted in a more mature phenotype such as Z bands, nascent intercalated discs and gap junctions. Before shifting to the cardiomyocyte phenotype, this system could accelerate apoptosis of the cell population (P<0.01). The inductive efficacy of this system can provide an opportunity to facilitate cardiomyocyte differentiation of ES cells. The inducible effects of this system may depend on increasing cardiac-specific gene expression and the induction of apoptosis in cells that are not committed to cardiac differentiation.

Animals↗
PubMed2006

Early lineage segregation between epiblast and primitive endoderm in mouse blastocysts through the Grb2-MAPK pathway.

It has been thought that early inner cell mass (ICM) is a homogeneous population and that cell position in the ICM leads to the formation of two lineages, epiblast (EPI) and primitive endoderm (PE), by E4.5. Here, however, we show that the ICM at E3.5 is already heterogeneous. The EPI- and PE-specific transcription factors, Nanog and Gata6, were expressed in the ICM in a random "salt and pepper" pattern, as early as E3.5, in a mutually exclusive manner. Lineage tracing showed predominant lineage restriction of single ICM cells at E3.5 to either lineage. In embryos lacking Grb2 where no PE forms, Gata6 expression was lost and all ICM cells were Nanog positive. We propose a model in which the ICM develops as a mosaic of EPI and PE progenitors at E3.5, dependent on Grb2-Ras-MAP kinase signaling, followed by later segregation of the progenitors into the appropriate cell layers.

Animals↗
PubMed2005

Endodermal sinus tumor of the ovary: the Hacettepe University experience.

OBJECTIVE: The purpose of this study was to evaluate the treatment regimens used for patients with endodermal sinus tumors (EST), and also to examine the prognostic value of surgicopathological variables. STUDY DESIGN: Twenty-two patients treated for pure EST, and seven patients who had mixed germ cell tumors with EST components were included. Initial surgery consisting of surgical staging to achieve optimal debulking was the principal mode of therapy. Data were obtained from patients' files, a special gynecologic oncology database, and pathology records. RESULTS: The median age at the time of diagnosis was 18 (range 8-45). Sixteen patients had stage I (55%), and 13 (45%) had stage II-IV disease. As an adjuvant therapy 18 patients (62%) received platin-based chemotherapy, three patients (10%) had non-platin-based chemotherapy, four patients (14%) had radiotherapy, and four patients (14%) had combined radiotherapy plus non-platin-based chemotherapy. The 5-year disease-free and overall survival rates were 47 and 48%, respectively. Survival rates were dismal in patients with stage II-IV disease (P < 0.001). Platin-based chemotherapy achieved significant survival benefit (P = 0.03 and P < 0.001, respectively). Fertility-saving surgery had an overall survival no worse than those who underwent more extensive surgery. There was no significant survival difference with respect to age, histology, and tumor size. CONCLUSION: Fertility-sparing surgery with a postoperative platin-based combination chemotherapy should be the selected mode of treatment.

Adolescent↗
PubMed2006

Regionalised signalling within the extraembryonic ectoderm regulates anterior visceral endoderm positioning in the mouse embryo.

The development of the anterior-posterior (AP) axis in the mammalian embryo is controlled by interactions between embryonic and extraembryonic tissues. It is well established that one of these extraembryonic tissues, the anterior visceral endoderm (AVE), can repress posterior cell fate and that signalling from the other, the extraembryonic ectoderm (ExE), is required for posterior patterning. Here, we show that signals from the prospective posterior ExE repress AVE gene expression and affect the distribution of the AVE cells. Surgical ablation of the prospective posterior, but not the anterior, extraembryonic region at 5.5 days of development (E5.5) perturbs the characteristic distal-to-anterior distribution of AVE cells and leads to a dramatic expansion of the AVE domain. Time-lapse imaging studies show that this increase is due to the ectopic expression of an AVE marker, which results in a symmetrical positioning of the AVE. Surgical ablation of this same ExE region after the distal-to-anterior migration has already commenced, at E5.75, does not affect the localisation of the AVE, indicating that this effect takes place within a short time window. Conversely, transplanting the prospective posterior, but not the anterior, extraembryonic region onto isolated E5.5 embryonic explants drastically reduces the AVE domain. Further, transplantation experiments demonstrate that the signalling regulating AVE gene expression originates from the posterior ExE, rather than its surrounding VE. Together, our results show that signals emanating from the future posterior ExE within a temporal window both restrict the AVE domain and promote its specific positioning. This indicates for the first time that the ExE is already regionalised a day before the onset of gastrulation in order to correctly set the orientation of the AP axis of the mouse embryo. We propose a reciprocal function of the posterior ExE and the AVE in establishing a balance between the antagonistic activities of these two tissues, essential for AP patterning.

Animals↗
PubMed2003

A study of regional gut endoderm potency by analysis of Cdx2 null mutant chimaeric mice.

Inactivation of Cdx2 by homologous recombination results in the development of forestomach epithelium at ectopic sites in pericaecal areas of the midgut of heterozygote mice. Local factors subsequently result in the secondary induction of tissues exhibiting an orderly sequence of tissue types between the ectopic forestomach tissue and the surrounding colon. Clonal analysis of this secondarily generated tissue using Y chromosome painting in chimaeric mice indicates that once differentiated to express Cdx2, host colonic epithelium can only form small intestinal-type epithelium, while Cdx2 mutant cells give rise to a succession of gastric-type tissue but never to a small intestine morphology. Our results indicate a difference in potency between forestomach and midgut precursor endodermal cells.

Animals↗
PubMed1996

Clinical experience with conservative surgery for vaginal endodermal sinus tumor.

Two cases of vaginal endodermal sinus tumor (EST), a rare pediatric malignancy, were managed with conservative surgery followed by adjuvant chemotherapy. The first case involved a 9-month-old girl with EST of the vagina, who was treated with a partial vaginectomy and VAC regimen (vincristine, actinomycin D, cyclophosphamide) during a 2-year period. The serum alpha-fetoprotein (AFP) level returned to normal after excision of the tumor, and it remained normal throughout the treatment period. There was no evidence of disease 30 months after diagnosis. The second case involved an 8-month-old girl with EST of the vagina, who was treated with local excision of the mass through a vaginotomy. The VAC regimen was administered, but the serum AFP level remained elevated. A follow-up abdominopelvic computed tomography scan, taken 4 months after the operation, showed local recurrence of the tumor. The VAC regimen was then changed to a BEP regimen (bleomycin, etoposide, cisplatin). The serum AFP level returned to normal after 2 courses of the new regimen, and no tumor was visible on the follow-up magnetic resonance imaging study. For vaginal EST, primary conservative surgery and adjuvant chemotherapy are attractive measures to preserve both reproductive and sexual function. The extent of conservative surgery requires at least a partial vaginectomy. Simple tumor excision may not be adequate to achieve cure or to prevent local recurrence, even with adjuvant chemotherapy. The serum AFP level is useful for diagnosing and monitoring vaginal EST in the infant.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1996

Endodermal sinus tumor in children.

Malignant germ cell tumors account for about 3% of neoplasms in children, and endodermal sinus tumor (EST) is the most common histological subtype. The authors reviewed 22 years' experience (at their institution) in the management of 37 patients with this tumor. Fifteen of them (41%) had a sacrococcygeal primary, 10 had a testicular tumor (27%), 6 had an ovarian tumor (16%), 3 had a vaginal tumor (8%) and 3 had tumors at other sites (8%). Seven (19%) patients presented with metastatic disease, primarily pulmonary. The serum alpha-fetoprotein (AFP) level was elevated in all cases tested. The initial chemotherapy regimen included vincristine, actinomycin, cyclophosphamide (VAC), and Adriamycin (6 patients), but since 1985 the regimen has been changed to include cisplatin or Carboplatin, etoposide, and bleomycin (21 patients). Eight patients with testicular tumors initially were treated with surgical excision alone. Computed tomography results were a poor predictor of recurrence, but AFP surveillance was extremely sensitive. No second-look operation detected residual tumor in the absence of AFP elevation. Initial relapse for all patients tended to occur early (within 2 years), locally, and often with pulmonary metastases. Although historically the prognosis for patients with EST has been poor, the overall 2-year survival rate in this series was 70%. The best prognosis was among the children who had a testicular primary tumor (survival rate, 100%). The 2-year survival rate for patients with ovarian tumors was 67%; for those with sacrococcygeal primaries it was 60%. These results suggest that the prognosis for children with EST has improved significantly over the past decade. Contributing factors include therapy based on cisplatin, etoposide, and bleomycin, and relapse surveillance with serial AFP determinations. Second-look procedures should be reserved for patients who have an increasing level of serum AFP, suspicious computed tomography findings, and no obvious evidence of metastatic disease.

Adolescent↗
PubMed1994

Evidence that Fc gamma receptors in rabbit yolk sac endoderm do not depend upon an acid pH to effect IgG binding and transcytosis in vitro.

An in vitro culture system has been devised creating apical and basal compartments separated by rabbit visceral yolk sac (VYS) with an intact epithelium. Selective transcytosis and binding of heterologous IgG applied to the apical yolk sac endoderm (YSE) was demonstrated in vitro using double label immunofluorescence. Thus, whilst both human and bovine IgG could be detected in endosomes in YSE, only human IgG could be detected in the basement membrane and vascular mesenchyme. This mirrors what is found in vivo. The Fc fragment of human Ig was transcytosed but not the Fab fragment, indicating that Fc receptors were expressed in the cultured YSE. When VYS was previously chilled to 4 degrees C to prevent endocytosis and treated with rabbit serum albumin to prevent non-specific binding, human IgG, but not bovine IgG, became specifically bound to YSE apical plasma membrane; comparison of binding at pH 6.0, 7.3 (the average pH of rabbit uterine fluid) and 8.0 revealed no obvious difference. Pre-exposure of VYS for up to 5 min in monensin, followed by culture in monensin and immunoglobulin-containing medium, did not prevent the selective transcystosis of human IgG, suggesting that an acidic compartment may not be needed for transcytosis. An acid pH dependent Fc gamma receptor equivalent to that on suckling rat gut jejunal enterocyte plasma membranes could not be isolated from rabbit YSE following exposure of solubilized membrane to affinity matrix bound IgG at pH 6.0 and elution at pH 8.0. These results contradict a recent suggestion that Fc receptors on all IgG transcytosing epithelia require an acid pH to effect IgG binding and selective transcytosis.

Animals↗
PubMed1982

Stimulation of retinoic acid of synthesis and turnover of basement membrane in mouse embryonal carcinoma-derived endoderm cells.

The effect of retinoic acid on the synthesis and degradation of basement membrane components by endoderm cells derived from mouse embryonal carcinoma (EC) cells was studied in a serum-free, defined medium. By immunofluorescence these cells accumulate type IV collagen, laminin, and fibronectin after growth in media containing epidermal growth factor (EGF), fibroblast growth factor (FGF), insulin, transferrin, and Pedersen fetuin. Collagen accounted for 2 to 4% of the newly synthesized proteins, of which 90% were found in the culture media. This collagen was identified as Pro-type IV be gel electrophoresis and enzymatic susceptibility. The EC cells preferentially attached to type IV collagen in vitro and such attachment was mediated by laminin. Treatment of EC cells with retinoic acid caused an increased accumulation of collagen (10 to 15% of secreted proteins) and also stimulated the elaboration of latent protease which degraded laminin and type IV collagen. The laminin-degrading activity was plasminogen dependent. The type IV collagen-degrading activity was a metal protease which could be activated by trypsin or plasmin. It is likely that at least part of the laminin degrading activity is plasmin (mediated through plasminogen activator), since highly purified plasmin is shown to degrade native laminin.

Animals↗
PubMed2001

A gene trap integration provides an early in situ marker for hepatic specification of the foregut endoderm.

We report the characterization of a gene trap integration that provides an in situ marker for one of the earliest events in liver development. Expression of the reporter gene is observed at the nine-somite stage in the hepatic field of the foregut endoderm. At 10.5 days post-coitus expression is observed exclusively and at high levels in the majority of cells in the developing liver bud. As development proceeds the proportion of expressing cells decreases with expression in adult liver being restricted to a few sporadic cells. This therefore provides the earliest, most specific in situ marker of the hepatic lineage reported to date and will be useful in the further characterization of the inductive events involved in hepatic specification. Molecular characterization of the gene trap insertion suggests that the expression pattern is the result of alternative promoter use in the ankyrin repeat-containing gene, gtar.

Amino Acid Sequence↗
PubMed2003

Down-regulation of endodermal Shh is required for gland formation in chicken stomach.

During the development of the proventriculus (glandular stomach) of the chicken embryo, the endodermal epithelium invades into the surrounding mesenchyme and forms glands. The glandular epithelial cells produce pepsinogen, while the non-glandular (luminal) epithelial cells secrete mucus. Sonic hedgehog is expressed uniformly in the proventricular epithelium before gland formation, but its expression ceases in gland cells. Here we present evidence that down-regulation of Sonic hedgehog is necessary for gland formation in the epithelium using a specific inhibitor of Sonic hedgehog signaling and virus mediated overexpression of Sonic hedgehog. We also show that gland formation is not induced by down-regulation of Sonic hedgehog alone; a mesenchymal influence is also required.

Animals↗
PubMed1998

Expression of NK-2 class homeobox gene Nkx2-6 in foregut endoderm and heart.

NK-2 class homeobox genes are candidate patterning and lineage regulators in diverse organisms. We report here the embryonic expression pattern of murine member, Nkx2-6. In keeping with its vertebrate relatives, Nkx2-6 was transcribed in ventrolateral embryonic structures. Expression was first detected at E8.0 in endodermal walls of the foregut pocket, tissue destined to become pharyngeal floor. From E8.0-10.5, transcripts were concentrated in pharyngeal pouches and juxtaposed arch ectoderm and mesoderm, as well as in more caudal gut segments. Expression was also seen at opposite poles of the developing heart from E8-8.5 in posterior myocardial progenitors, then sinus venosa and dorsal pericardium, and from E9.5 in outflow tract myocardium.

Animals↗
PubMed1998

Highly restricted expression at the ectoderm-endoderm boundary of PIHbox 9, a sea urchin homeobox gene related to the human HB9 gene.

Characterisation of a sea urchin (P. lividus) homeobox gene PIHbox 9 is reported. The homeodomain of PIHbox9 is 95% identical to the homeodomain of the human HB9 gene, indicating that the two genes are highly related. Temporal expression analysis during sea urchin embryogenesis showed an absence of transcripts at early cleavage stages. At late gastrula stage, transcripts were barely detectable and reached the highest abundance at prism/early pluteus stages. By whole mount in situ hybridisation we observed a highly restricted expression in a few cells of the ectoderm-endoderm boundary of embryos at the prism stage. At pluteus stages, expression of PIHbox 9 was confined around the anus.

Animals↗
PubMed2002

Expression of the Wnt inhibitor, sFRP5, in the gut endoderm of Xenopus.

Signaling by the Wnt family of secreted growth factors is involved in numerous different aspects of embryonic development and also for maintenance of cellular function in adult tissues. In addition to regulation at the transcriptional level, Wnt activity is modulated by a number of different Wnt-binding proteins. Here we report the cloning and developmental expression pattern of the Xenopus orthologue of secreted Frizzled-related protein 5 (sFRP5), an endogenous inhibitor of Wnt signaling. At early stages of endodermal differentiation, sFRP5 is expressed in the developing liver. At later stages however, sFRP5 expression is down-regulated in the liver and becomes strongly expressed in the region corresponding to the junction between the posterior portion of the stomach and the anterior intestines.

Adaptor Proteins, Signal Transducing↗
PubMedDate not supplied

Co-expression of vimentin and cytokeratins in parietal endoderm cells of early mouse embryo.

Of the five classes of intermediate filaments found in vertebrate tissues, the cytokeratins are considered unique to epithelial tissues, while vimentin is expressed by endothelial and mesenchymal cells. In neither case is the precise function of the filament system known. Epithelial cells in culture often express vimentin as well as cytokeratins, but co-expression in vivo, as reported for pleomorphic adenomas of the parotid gland and metastatic carcinoma cells in ascites or pleural fluid, is still controversial. Here we report the co-expression of cytokeratins and vimentin in situ, in the parietal endoderm of the mouse embryo 8.5-13.5 days old. This population of individual, motile cells seems to be derived from a conventional epithelium by migration and differentiation. Our results support the idea that vimentin expression is specifically related to reduced cell-to-cell contact, and to the independent existence of a cell following detachment from an epithelial sheet.

Animals↗